Genetics Flashcards
What is the name of the small self-replicating DNA molecule found in bacteria that can be used as a cloning vector
Plasmid
DNA agarose gel electrophoresis
DNA migrates from the negative to the positive electrode
Ultraviolet (UV) light is used to visualise the DNA bands in the gel
Ethidium bromide binds to the double stranded DNA
Smaller DNA molecules migrate faster than larger DNA molecules
What enzyme is used to seal the DNA sugar phosphate backbone between the cloning vector DNA and the DNA insert during molecular cloning
DNA ligase
What is the theoretical number of polymer chain reaction (PCR) amplicons expected after forty cycles with a starting number of 1 target sequence
c) 1 X 2^40 = 1,099,511,627,776
5) During a typical polymerase chain reaction (PCR) cycle DNA samples are first heated to 94oC and then cooled to 55oC and then heated again to 72oC. What are each of the different temperature steps
c) 94oC = DNA denaturation step 55oC = primer annealing step 72oC = enzyme extension step
Components of a typical PCR reaction
Taq DNA polymerase enzyme
dATP,dCTP, dGTP, and dTTP nucleotides
Synthetic single stranded oligonucleotide DNA primers
The method of sequencing DNA using dideoxynucleotide triphosphates (ddNTPs) is called what
The Sanger DNA sequencing method
What is the correct name for the widely used gene that allows bacterial colonies carrying a DNA insert to be selected during the molecular cloning process based on their ability to metabolise the sugar X gal
LacZ
What is the target region of a genome that is amplified during the polymerase chain reaction (PCR)
Amplicon
Nitrogenous bases found in biological DNA
Adenine, Guanine, Cytosine and Thymine
What is the function of the enzyme DNA polymerases
Catalyses the synthesis of a new DNA molecule using a template DNA strand
What is the full term for the acronym mRNA
Messenger ribonucleic acid
The biochemical process of translation is carried out by which molecule
The ribosome
Examine the coding DNA sequence of a gene below (note only one of the strands is shown). A mutation has been discovered in this gene which changes a guanine nucleotide (G) to a adenine nucleotide (A) (Note the mutation is highlighted in underline and bold). The coding sequence of the normal gene and the mutated sequence of the gene are shown
Normal DNA sequence: TAC GGG CCC GTG
Normal mRNA sequence: AUG CCC GGG CAC
Normal polypeptide sequence: Met Pro Gly His
Mutant DNA sequence: TAC GG CCC GTA
Mutant mRNA sequence: AUG CCC GGG CAU
Mutant polypeptide sequence: Met Pro Gly His
Silent mutation
When snapdragon plants that produce red flowers are crossed with snapdragon plants that produce white flowers the resulting offspring produce pink flowers. What Is the genetic term used to describe this phenomenon
Incomplete dominance
Who is considered to be the father of genetics
Gregor Mendel
What is the meaning of the genetic term epistasis
One gene alters the expression of another gene
What is the correct description for a diploid organism with a pair of identical alleles for a character
Homozygous
Do prokaryotic cells produce a nuclear membrane?
No
How many rounds of cell division take place in eukaryotic meiotic cell division
2
The chromatin in eukaryotic cell nuclei consists of ——-
DNA and Protein
If mottled overo stallions are matted with mottled overo mares what would the phenotypic proportions of foals born
50% mottled overo foals 25% solid coloured foals 25% pure white still born foals
A scientist crosses two true breeding varieties of pea plant. The first variety consists of plants that always produce yellow and round seeds. The second variety consists of plants that always produce green and wrinkled seeds. The F1 hybrid mating consists of plants that produce yellow and round seeds. What is the expected ratio of phenotypes in the F2 generation that is produced from mating the F1 plants with each other
9 Yellow Round 3 Yellow Wrinkled 3 Green Round 1 Green Wrinkled
What does r RNA stand for
Ribosomal RNA
What is the definition of the term cell cycle
The series of events in a eukaryotic cell from one cell division to the next
The ovine haploid chromosome number is 27. Ignoring recombination how many chromosomal combinations can result during meitotic cell division in sheep
2^27 = 134,217,728
What is the term used to describe the genotype of an X linked gene in male mammals
Hemizygous
What is the definition of the term pleiotrophy
The genetic effect of a single gene on multiple phenotypic traits
What process can enhance the evolutionary adaptation of a species to its environment
Natural or artifical selection
The frequency of cystic fibrosis (a recessive genetic disorder) in Ireland is approximately 1 in 1600. Therefore assuming Hardy-Weinberg Equilibrium which of the answers below represents the best estimate of the frequency of the mutant cystic fibrosis allele in the Irish population
0.025
Who first developed the concept of the genetic linkage map
Thomas Hunt Morgan and Alfred Sturtevant
A colour blind woman has children with a man who has normal vision. What are the expected offspring proportions from this mating
50% carrier females 50% colour blind males
S Wright, J.B.S Haldane and R.A fisher initiated which branch of genetics
Population genetics
In a region of west Africa with a high incidence of malaria, the frequency of sickle cell anaemia (a recessive genetic disorder) in the human population is 1 in 30. Therefore assuming Hardy Weinberg Equation (HWE) which of the answers below represents the best estimate of the mutant sickle cell anaemia in this population
0.18
Scientific evidence suggests that the cheetah (Acinoyx Jubatus) has undergone how many population constrictions that led to reductions in genetic variation
2
An evolutionary founder event will act to
Increase genetic drift
What is the definition of the term genetic linkage
The relationship between two genes that are physically close on the same chromosome and tend to be transmitted from parents to offspring as a single unit
What are removed from transcribed protein coding RNA during mRNA processing in eukaryotes
Introns
What can cause mutation in the sequence or structure of DNA molecules
Exposure to chemical mutagen
Exposure to X Ray radiation
Exposure to Ultra Violet (UV) radiation
The biochemical process of transcription is carried out by which molecule
RNA polymerase
The ribosome is composed of
Protein and RNA
Who discovered the three dimensional structure of DNA
James Watson and Francis Crick
Terms relating to the structure of DNA
Hydrogen bond
Purine
Pyrimidine
What is the function of the retroviral enzyme reverse transcriptase
Transcribes a DNA molecule from a single stranded viral RNA template
What is the Sanger laboratory method used for
Determining the sequence of bases in a DNA molecule
What is the theoretical number of polymerase chain reaction (PCR) amplicons expected after 40 cycles with a starting number of 10 sequences
10 X 2^40= 10, 995, 116, 277, 760
Which is the name for a widely used gene that confers resistance to an antibiotic during bacterial cloning of recombinant DNA
amp^R
Methods used to produce transgenic animals
Microinjection of foreign DNA into embryo pro nuclei
Replacement of an oocyte nucleus with the nucleus of a transgenic donor cell
Use of modified retroviruses as vectors to carry genes into an embryo
What bacterial species can be used to produce transgenic plants using recombinant TI plasmids
Agrobacterium tumefaciens
What does the Ti stand for in Ti plasmid
Tumour inducing
Transgenic golden rice was developed to alleviate deficiency of what vitamin in certain human populations
Vit A
Processes that occur in the eukaryotic cells nucleus
DNA replication, RNA processing, Transcription
With respect to population genetics, a gene pool consists of
The total of all alleles across all genetic loci in a population
What was the mechanism of the evolution of species proposed by Charles Darwin in the Origin of Species published in 1859
Natural Selection
Characteristics of a codon
Its consists of three nucleotides
It never codes for one or more amino acids
It’s the basic unit of genetic code
Cellular components involved in translation
Mature mRNA
tRNA
Ribosomes
The anticodon of a particular tRNA molecule is
Complementary to the corresponding mRNA molecule
What is the size of the haploid human genome in base pairs
3.2 Giga base pairs (Gbp)
The combined human genome consists of the nuclear genome and the ….
Mitochondrial genome
What is meant by the term genetic drift
The random fluctuations in a populations genetic structure due to chance over time
Examine the following mature m RNA sequence 5’ AUG-AAA-GCG-UUU-UGA-3’. Using genetic code what is the correct sequence of amino acids specified by this frame
MET – LYS – ALA- SER – PHE – STOP
Genetic studies have revealed a death of genetic variation in the Northern Elephant Seal populations. What is the major contributing factor that has resulted in this lack of variation
A major population bottleneck effect in the 19th Century
What force of microevolution permits populations to become better adapted to their environment
Natural Selection
What are the correct temperatures at each stage of a typical PCR reaction
Temp A = 55oC Temp B= 72oC Temp C =94oC
Flower colour in peas is controlled by a single gene for which there are two alleles P=Purple and p=white. Purple flower colour is dominant to white. The plant is homozygous for purple and for white flowers. What are the expected genotype frequencies of the offspring
All offspring will have a Pp genotype
A point mutation which causes the reading frame of m RNA molecule to be altered is called
Frameshift mutation
Physical and chemical agents that are mutagens
UV light
X Ray
Atomic Radiation
What enzyme is responsible for synthesising m RNA under the direction of the genes DNA sequence
RNA polymerase
How many stop codons are there in the genetic code
3
Conditions of the Hardy Weinberg Theorem (HWE)
The population must be very large
No natural selection occurs in the population
Random mating is occurring in the population
The biochemical process of transcription is carried out by which molecule
RNA polymerase
How many start and stop codons are there in the genetic code
4
What is the name given to a model of DNA replication whereby the two DNA strand parental molecule separate and each single strand then functions as a template for the new complementary strand
Semi conservative replication
What molecule is responsible for transferring the correct amino acid at the size of translation
Transfer RNA
Under the assumption of the Hardy Weinberg Equation (HWE) what would be the expected genotypic frequencies for a gene with two alleles (A and a) where the frequency of A allele p is 0.60 and the frequency of the a allele q is 0.40
AA = 0.36 aa = 0.16 Aa = 0.48
The bovine haploid number is 30. Ignoring recombination how many chromosomal combinations can result during meitotic cell division in cattle
2^30 = 1,073,741,824
What codon sequence represents the eukaryotic START codon
AUG
What does DNA stand for
Deoxyribonucleic acid
James Watson and Francis Crick along with Maurice Wilkins won the Nobel Prize in 1962 for what scientific breakthrough reported in 1953
The elucidation of the 3 dimensional structure of DNA
Description of metaphase in mitosis
The cells chromosomes align along a central plain in the dividing cell
During the cell cycle when is the cells genetic material (i.e. the genome) replicated
S phase
Colour blindness in humans is an X linked recessive disorder. A female who is colour blind marries a colour blind man. If the couple have children what will the phenotypes of the offspring be
All children will be colour blind
When short horn cattle with red coat colour are bred with short horn cattle with white coat the resulting progeny all display roan coat colour in which red hairs are intermingled with white hairs. This genetic phenomenon is an example of
Co-dominance
What is mitosis
A form of cell division in which a diploid parent gives rise to two genetically identical daughter cells
Functions of mitosis
Cell repair
Organism growth
Organism development
Composition of chromatin
A complex of DNA and protein
What is the name of the pentose sugar found in DNA
Deoxyribose
What is the name of the organelle that facilitates the translation of messenger RNA into a polypeptide
Ribosome
What is meiosis
A form of cell division in which a diploid parent cell gives rise to four genetically different haploid gametes
Haploid number of human chromosome
n = 23
Factors that contribute to the genetic variation that arises between generations
Independent assortment of chromosomes during meiosis
The crossing over of non -sister chromatids during meiosis
Random fertilisation of gametes
What molecule is responsible for transferring the correct amino acid at the site of a codon during translation
tRNA
Who wrote the book on the origin of the species
Charles Darwin
The frequency of a recessive genetic disease causing allele q in a population is estimated at 0.2. The population is comprised of 1000 individuals. Assuming Hardy Weinberg Equation how many individuals are predicted to be affected by the disorder.
40
Positive natural selection will act to…
Increase the frequency of a favourite allele in a population
What’s the most extreme form of inbreeding
Self-fertilisation
Microevolution definition
The change in allele and/or genotype frequencies of a population from one generation to the next
What’s the phenomenon called where some transfer RNA anticodons recognise two or more different codons
Wobble
Sequence of events during the process of gene expression
DNA – RNA – polypeptide – protein
What insect is considered to be the workhorse of genetics
The fruit fly (Drosophilia Monogaster)
Who first developed the concept of the genetic map
Thomas Hunt Morgan and Alfred Sturtevant
What percentage of transgenic offspring would be expected using transgenesis by transfer of transfected nuclei?
1-5%
A coenocyte is…
A multinucleated cell generated from multiple nuclear divisions without cytokinesis
What is the theoretical number of polymerase chain reaction (PCR) amplicons expected after 35 cycles with a starting number of 20 target sequences?
20 x 2^35 = 687,194,767,360
The dwarf phenotype in Dexter cattle is associated with a lethal recessive allele. The lethal recessive condition is termed ‘bulldog’, which gives rise to stillborn calves with severe facial deformities. Male dwarf Dexter cattle are crossed with female dwarf Dexter cattle. What would be the expected phenotypic proportions of the offspring produced?
50% dwarf calves | 25% normal-sized calves | 25% stillborn ‘bulldog’ calves
ABO blood group system in humans is controlled by…
Controlled by a single gene with two codominant alleles and one recessive allele
What term relates to the structure of double-stranded DNA?
Hydrogen bond
Alan and Betty are both carriers (heterozygotes) for a recessive genetic disorder. If Alan and Betty have two children, what is the probability that only one of the two children will be affected by this genetic disorder?
0.2500
Sickle cell anaemia (a recessive genetic disorder) affects approximately 1 in 130 people in Cameroon, a country in West Africa. Therefore, assuming HardyWeinberg Equilibrium (HWE), which of the answers below represents the best estimate of the frequency of the mutant sickle cell allele in the Cameroonian population?
0.088
The genetic distance between two genes is 7 centimorgans (cM). What is the expected recombination frequency between these two genes?
0.07
Who showed that the material in dead bacterial cells that can genetically transform living bacterial cells is actually DNA?
Oswald Avery, Colin MacLeod, and Maclyn McCarthy
A colour-blind man has children with a woman who is a carrier for this genetic trait. What are the expected offspring proportions from this mating?
50% carrier females | 25% colour-blind males | 25% normal males
The incidence of cystic fibrosis (a recessive genetic disorder) in Germany is approximately 1 in 3,300. Therefore, assuming Hardy-Weinberg Equilibrium (HWE), which of the answers below represents the best estimate of the frequency of the mutant cystic fibrosis allele in the German population?
0.0174
The term endosymbiosis refers to what biological phenomena?
A scientific theory for the origin of eukaryotic mitochondria and chloroplasts
The term ‘semi-conservative’ is used to refer to the mechanism governing which of the following molecular biological processes?
Replication of DNA
Under the assumption of Hardy-Weinberg equilibrium (HWE), what would be the expected genotype frequencies for a gene with two alleles (‘A’ and ‘a’) where the frequency of the ‘A’ allele (p) is 0.70 and the frequency of the ‘a’ allele (q) is 0.30?
AA = 0.49
aa = 0.09
Aa = 0.42
